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Dec 6, 2012 11:00am PST
. narrator: the lower rates of deforestation are based overnmen ctrcin the environmental laws on the books. brazil has received some help from some new technology and from other ecologists, including chris uhl. uhl is the founder of imazon, a research institute located in the city of belém. the law in pará state says that 50% of all prate land must be maintained in forest. until recently, that was very hd to monitor. now, using a system of satellites casearcher carlos sousaiing cadot, okgps is realowhat it allows us to do is to pickp signals from the satellites. and through ocess of triangulation we can locate ouels rylynr and through ocess to within about ten meters. four... ey've gour sateites now. we are... probably... in this... area. mm-hmm. narrator: if the government chooses, it can use gps to locate property lines on satlite photographs of the landscape. they can then determine how much of a farmer's land has beenleared but enforcement is stty. anotg problem is thenefficient way the cleared land is being used. the most common farming and grazing method here requires the
Dec 6, 2012 8:00am PST
they call it neptunium? you know what the first planet was they discovered in terms of newton's laws? neptune, gang. neptune. so they call this neptunium. first element beyond uranium and that's neptunium 239. it's got a very, very short half-life. and you know what it does? it decays. and guess what it emits? begins with a b. no, not alpha. try it again. it emits a beta particle. okay. it emits a beta particle. and what does it turn into? how many people can figure out what the number is here that couldn't do it before but maybe now can? show of hands. four people. wonderful. now, how many? what is it gonna be, gang? it's 94. 94, 94. what is the second planet that we named after discovering by newton's laws? it wasn't neptune, it was what? - pluto. - pluto. guess what we'd be calling this, gang? plutonium. plutonium. pu239. and you know what plutonium will do? plutonium as well as uranium 235 will undergo fission when a neutron taps it. and so this is used for power production. u235, used for power production. historically, when the bombs were dropped back in world war ii, the bomb
Dec 5, 2012 8:00am PST
postulate: all the laws of physics will be seen to be the same in uniformly moving reference frames. this is moving uniformly with respect to this. in fact, einstein said, it makes no difference whether this is at rest and this is moving or this is at rest and this is moving away. motion really is relative. it's a relative motion between the planet and the ship. so, let me ask you a question. these six minute flashes that the ship really is sending-- really is sending the six, we agreed on that before-- these six minute flashes are gonna be seen how long apart by that person back here, who's now looking, who puts the telescope up and takes a look? check your neighbor. what's the answer, gang? - 12. - 12. you see that. i mean if 6 is seen as 12, then 6 will be seen as 12. so we can complete this diagram up here and say this. we have another planet here. a person watching these flashes, okay? what happens? really the flashes are like this, okay? they're all scrunched up in here and all dragged out here. and so, six minutes will be seen three for approach, but for a recession, 12 minut
Search Results 0 to 2 of about 3